This invention relates to a ground engaging stud for an endless snowmobile drive track and more particularly to a stud and method of making a stud which has radially, outwardly flaring, curvilinear teeth mounted on a central mounting hub.
Snowmobiles are propelled by endless, ground engaging drive belts. Ice gripping studs have been mounted on the outer surface of the belt to enhance traction, particularly during snowmobile races such as the 500 mile snowmobile race conducted annually in Sault Ste. Marie, Mich. To maximize surface ice penetration, it is important that the stud include ice penetrating teeth which will penetrate hard ice on which the snowmobile travels. A stud constructed according to the present invention is provided with a plurality of individual, elongate teeth circumferentially disposed about a longitudinal stud axis which is generally perpendicular to the snowmobile drive belt, and the surface being traversed.
The traction capabilities of the stud is greatly enhanced if the teeth flare radially outwardly. With a stud constructed according to the present invention, the teeth, as they wear, will be self-sharpening in a manner to be more particularly described hereinafter. A stud is disclosed in U.S. Pat. No. 3,572,851, granted Mar. 30, 1971 having ground engaging teeth which are generally perpendicular to a snowmobile drive belt. As this prior art stud negotiates the front drive roll of a snowmobile and the teeth initially engage the surface, the teeth are inclined rearwardly relative to the direction of belt travel and sometimes do not "dig in" but rather skip and jump over the surface. It has been found that, if the teeth are so flared that the attitude of the lead tooth of a given stud is generally vertical to the surface being traversed as the tooth negotiates the front drive sprocket of a snowmobile and initially engages the surface, the lead tooth will better penetrate the ice whereby traction is increased. Accordingly, it is the object of the present invention to provide a traction increasing stud for a snowmobile track including a plurality of perimetrically disposed, radially outwardly flaring, ground engaging teeth.
It is another object of the present invention to provide a snowmobile belt in combination with a stud having a lead tooth which is flared radially outwardly relative to the stud axis and mounted so as to be disposed generally vertical to the surface being traversed as the tooth engages the surface.
To strengthen the load bearing capabilities of the stud constructed according to the present invention, the individual teeth are bent into a circumferentially curvilinear, concavoconvex shape by bending a portion of a star shaped blank in a first direction out of the plane of the blank. The load bearing capabilities are further enhanced by bending a part of the previous bent blank portion in an opposite direction to provide a mounting hub having an annular rim which is generally vertical to the snowmobile belt and parallel to the stud axis. Accordingly, it is another object of the present invention to provide a stud for a snowmobile track including a plurality of radially outwardly flaring ice penetrating teeth mounted on a hollow, cylindrical hub wall which is adapted to be disposed generally perpendicular to the snowmobile drive belt.
It is a further object of the present invention to provide a one-piece stud of the type described including a plurality of radially outwardly flaring ground engaging teeth which are circumferentially curved to define concavo-convex teeth.
It is another object of the present invention to provide a one-piece stud of the type described having a plurality of ice penetrating teeth which flare outwardly in such a manner as to be self-sharpening as they wear.
It is another object of the present invention to provide a stud which will minimize the accumulation of ice within the stud.
It is another object of the present invention to provide a stud of the type described including an even number of individual, ground engaging teeth.
It is another object of the present invention to provide a method of making a stud including bending a portion of the blank to form arcuate ice penetrating teeth and then bending a part of the bent portion in an opposite direction to form a cylindrical hub.
Other objects and advantages of the present invention will become apparent to those of ordinary skill and art as the description thereof proceeds.